278 PHYSIOGRAPHY OP CENTRAL-ASIAN DESERTS AND OASES.
THIRD EROSION CYCLE.
To us the third cycle is most interesting, as it overlaps the second glacial epoch and less time has elapsed to obliterate its records. As a result of its uplift, apparently warped, the river cut down through the alluvial fillings of the second
Fig. 455.--Ice-cave of the Zerafshan, Looking from within.
Fig. 456.—Terraces of the Zerafshan.
cycle and into the old rock bottom to a depth of from 5o feet in the lower to 300 feet in the mid-warp part of the valley with a canyon about as wide as the present and reaching about the same depth. Then the uplift appears to have stopped